SU540403A1 - Method of receiving bi-pulse signal - Google Patents

Description

one

The invention relates to telecommunications and is intended to recover a data signal from a bi-pulse signal.

A known method for receiving a bi-pulse signal, in which a subcarrier synchronization signal is extracted by analog or digital filtering from a received b pulse signal, dividing its frequency by two to obtain a reference signal, multiply the reference signal with the received bi-pulse signal 1.

The signal resulting from the multiplication, due to the ambiguity of the process of dividing the frequency by two, and the random initial phase of the divider can be in the forward or reverse phase. To eliminate reverse operation, special signal coding methods are used which complicate the apparatus and impair the noise immunity of the communication.

The purpose of the invention is to increase the reliability of reception and determine the magnitude of the signal of uncertainty at the current time.

For this, in a method in which the received bi-pulse signal is multiplied with a reference oscillation obtained by dividing the synchronization signal by the subcarrier extracted from the received bi-pulse signal by two frequencies,

using the subcarrier synchronization signal, half-symbols are recovered from the received bi-pulse signal, generate front pulses when the signs of the next semi-symbols coincide, generate an unreliability signal of the reference oscillation phase by comparative analysis of the front pulse phase and the reference oscillation phase, and when the unreliability signal is equal to

the critical value, and the front pulse, which is antiphase in the reference oscillation, are reversed in the phase of the reference oscillation. To determine the magnitude of the unreliability signal at the current time, the magnitude of the unreliability signal at the previous time point is summed to +1, if the phase of the front pulse is inverse to the phase of the reference oscillation, and the magnitude of the unreliability signal at the previous time point is less

the upper threshold value and is summed with the value -1, if the phase of the front pulse coincides with the phase of the reference oscillation, and the value of the previous signal of uncertainty is greater than the lower threshold value; at

in the remaining cases, the magnitude of the unreliability signal is left unchanged, and the critical value of the unreliability signal is equated to the upper threshold value.

The drawing shows a structural electrical circuit of a device implementing a method for receiving a bi-pulse signal.

The device contains a subcarrier synchronizer 1 for separating the subcarrier synchronization signal from the received bi-pulse signal, the output signal of which, together with the received signal, is fed to the edge selector of data signal 2, which generates edge pulses when the characters of adjacent semi-symbols coincide and consist of trigger 3, equivalent cell 4 and element And 5; uncertainty determiner 6, including And 7, 8 elements, counter 9 and switch 10, divider by two frequencies of the subcarrier synchronization signal 11, performed on a trigger and forming a reference oscillation modulo two 12. In the uncertainty determiner 6, the phase of the front pulse is compared and a reference oscillation and form an unreliability signal that changes the division phase of the trigger 11.

The method of receiving the bi-pulse signal is as follows.

A bi-pulse signal arrives at the input of the device such that the single character "unit" is encoded with the half-character "1 followed by the half-character" O, and the single character "zero" with the half-character "O followed by the half-character" 1. In the -synchronous subcarrier synchronization, the subcarrier synchronization signal with the repetition period - is extracted from the received bi-pulse signal,

where t is the duration of a unit interval.

By recovering half-symbols from the received bi-pulse signal using the subcarrier sync and delay signal

in trigger 3, the reference time

At the output of the edge of the data signal 2, the front pulses are generated at the output of the edge of the data signal. In addition, a subcarrier sync signal is applied to a trigger designed to form a reference signal. The reference signal sets the counting sign of the counter 9, which is used to determine the magnitude of the unreliability signal. The counting input of the counter counter 9 receives the fronts through an AND 7 element, designed to prohibit the cyclic transfer of the state of the counter 9 from the zero (lower threshold) STATE to the M-th (upper threshold) state and back, where.

To implement such a prohibition, the outputs of the counter 9 are connected through the switch 10 to the element And 7.

Reversal of the reference oscillation phase is performed by inhibiting the counting of the trigger 11, for which an inverted output is connected to its counting enable input.

element 8. At the output of the trigger 11, the reference signal has an unambiguous phase relative to the edges of the data signal, and the signal obtained by multiplying in the modulator two 12 reference signals with the received bipulse signal has only a direct phase.

Claims (2)

1. A method of receiving a bi-pulse signal, in which the received bi-pulse signal is multiplied with a reference oscillation, obtained as a result of dividing the subcarrier synchronization signal into two frequencies, extracted from the pr: received bi-pulse signal, characterized in that, in order to increase the reception accuracy, the half-symbols from the received bi-pulse signal are additionally restored using the subcarrier synchronization signal from the received bi-pulse signal half symbol form signal the unreliability of the phase of the reference oscillation by comparative analysis of the phase of the pulses of the front and the phase of the reference oscillation, and when the magnitude of the signal of unreliability is equal to a critical value, and the pulse of the front, anti-phase reference oscillation, change the phase of the reference oscillation on the reverse. 2. A method according to claim 1, characterized in that to determine the magnitude of the unreliability signal at the current time, the magnitude of the unreliability signal at the previous time is summed to +1, if the phase of the front pulse is inverse to the phase of the reference oscillation, and the magnitude of the uncertainty signal is previous time less than the upper threshold value, summed with the value -1, if the phase of the pulse of the front coincides with the phase of the reference oscillation, and the value of the previous signal of unreliability is greater than the lower threshold value; in other cases, the magnitude of the unreliability signal is left unchanged, with the critical value of the unreliability signal being equal to the upper threshold value. The source of information taken into account in the examination: 1. Static communication and its applications, edited by Balakrishnan A.V., Mir, 1967, p. 92 (prototype).